Photographic developing apparatus



Nov. 6, 1962 w. LIMBERGER 3,062,123

PHOTOGRAPHIC DEVELOPING APPARATUS Filed 0G11. 5, 1959 3 Sheets-Sheet 1 FIG.

EMT

Nov. 6, 1962 w. LIMBERGER PHoTocxAPHIc DEvELoPINc. APPARATUS 3 Sheets-Sheet 2 Filed Oct. 5, 1959 Nov. 6, 1962 w. LIMBERGER 3,062,123

PHOTOGRAPHIC DEVELOPING APPARATUS Filed Oct. 5, 1959 3 Sheets-Sheet 3 United States Patent O 3,062,123 PHOTOGRAPHIC DEVELOPING APPARATUS Walter Limberger, Hamburg, Germany, assignor to Lumuprint Kindler KG, Hamburg, Germany Filed Oct. 5, 1959, Ser. No. 844,405 Claims priority, application Germany Oct. 10, 1958 6 Claims. (Cl. 95-89) The invention relates to an apparatus for developing exposed photographic layers customarily applied to a carrier such as a sheet of paper, lms, or the like, in a liquid developing bath through which at least one carrier is passed with its layer. In particular the invention relates to such devices including a bath container for carrying out the development, a supply container for the developing liquid arranged below said bath container., a feed duct connecting the two containers, and a pump for forcing the developing liquid into the feed duct.

A developing device of this type may be built into a copying device which at the same time includes other means for producing a copy, for instance an exposure device, a drying device, or the like.

All these known developing devices are constructed in such a manner that, after the developing device has been switched off, the liquid in the bath container is returned to the supply container in order to minimize oxidation and evaporation. In order to solve this problem the known devices are rather complicated in construction and in addition do not work etliciently. Thus for instance it is known to provide a drain opening at the lowest point of the bath container which however is so small that, after the device has been switched off, only a Very slow diminution of the liquid level takes place. Such small openings constitute a disadvantage as they are prone to easily become clogged, and because special means are necessary to return the outowing liquid. Particularly with respect to the fact, that combined copying devices should require as little space as possible there arise arrangement problems if it is required to provide additional arts.

p One object of the invention is to provide an apparatus of this type permitting the use of a large capacity supply container, and to provide at the same time a depositing surface adjacent the developing apparatus.

Another object of the invention is to provide means allowing in an especially simple way to empty the bath container into the supply container after the developing apparatus has been stopped.

A further object of the invention is to provide means permitting a constant circulation of the developing liquid through the bath container and the supply container while the apparatus is operating.

Still another object of the invention is to minimize the influences of evaporation and oxidation of the developing liquid.

These objects are solved by the invention in that the feed duct is constructed so that it will automatically become effective as return duct as soon as the motor of the pump is switched off.

According to a preferred embodiment of the invention the feed duct communicating with the container extends above the bottom preferably into a sump provided at the bottom of the bath container.

According to an advantageous embodiment of the invention a pump is arranged within the feed duct said pump being provided with a by-path duct being closed while the pump is operating, and which is opened when the pump is switched off.

According to another advantageous embodiment of the invention a gear pump is used, the gears of which being arranged with suicient play that a returning flow of 'liquid may pass the pump itself.

The pump may for instance be arranged in an advantageous manner within a frame being suspended from above. In this case the pump may suitably be arranged within the lower part of said frame.

According to another embodiment of the invention the feed duct is led around the supply container, and the pump is arranged below the supply container.

According to a preferred embodiment the motor for the gear pump is arranged within an apparatus housing located above the supply container slidable or pivotal transversely so that said motor releasably connected to the pump shaft by a clutch may be moved free from the frame. It is to be understood that a gear pump of special design may be driven by the motor for the other apparatuses.

According to a preferred form of embodiment of the invention an overflow duct is provided between the supply container and the bath container so that the fluid will constantly circulate as long as the pump is operating. In this case the liquid level is determined by the mouth of thev return duct.

It is of advantage to have a floating cover provided within the supply container which, for instance, may be made of liquid tight cellular rubber, or cellular PVC (polyvinyl chloride). Another advantageous form of embodiment of said floating cover provides for forming it by several separate hollow lloating bodies, e.g. made of plastics.

According to an especially advantageous form of embodiment the supply container is formed to serve as an apparatus support for a developing or copying apparatus, having a surface corresponding to or exceeding the dimensions of the apparatuses, and showing a relatively small heightA Advantageously the arrangement is so, that an air gap is provided between the housing of the apparatuses and the supply container serving as support, said air gap being formed by feet provided on the housing of the apparatuses which are placed on the support, recesses or holding means being provided on the latter for fixing the feet. The overflow and feed duct as well as the drive shaft of the pump are extended through the bottom of the housing into the supporting frame. The supply container preferably consists of a material having a good heat conductivity, e.g. metal, so that the developing fluid is cooled, and in this connection it should be noted that the described form of the support has a surface as great as possible. The support is provided with feet, so that the air may also flow along the lower surface of the support.

In the aforedescribed advantageous arrangement a closeable opening has been provided in the bottom of the apparatus housing above the frame of the supply container, said opening being dimensioned in such a way, that the frame may be lifted out through the bottom of the supply container after the drive motor of the pump has been swung sidewardly.

According to a special form of embodiment of the invention no overflow duct is provided but control means for the pump drive or the feed duct in dependence upon the liquid level. This control means may comprise a float within the bath container which will switch the motor on or olf upon reaching the predetermined liquid level depending whether it is falling or rising. In apparatus in which an exact maintenance of the liquid level is not essential a certain range of the liquid level may be permissible by, for instance, using a corresponding delay of switching the motor or permitting the float lever to pivot a certain distance before actuating the switch.

A special object of the invention is the provision of a developing apparatus comprising a table on the plate of which the apparatus housing of the developing apparatus is placed, and beneath the plate of which a cabinet for receiving the supply container is arranged. This plate is suitably provided with an opening through which the communicating ducts between the supply container and the bath container extend. This opening is located within the cabinet. Furthermore it is of advantage that the cabinet only extends over one half of the space below the table plate, so that the operating person may sit in front of the apparatus and place the legs below the table.

Further advantages and features of the invention will become apparent from the following description of two forms of embodiment which are shown in the drawings and given by way of example only.

In the drawings:

FIG. 1 shows a sectional side View of the apparatus in accordance with the invention;

FIG. 2 shows a partial view partly sectioned of the supply container as seen from the top;

FIG. 3 shows a sectional side view of another form of embodiment in accordance with the invention;

FIG. 4 shows a sectional view of a supply container, corresponding for instance to the form of embodiment shown in FIG. 3.

In FIGS. l and 2 the supply container is formed to serve as an apparatus support 1 which is relatively flat and extends somewhat beyond the base surface of the apparatus housing 2. rIhe supply container 1 stands on feet 3, 4 so that air may stream along its lower surface. In the bottom of the supply -container a sump 5 is formed. An opening is provided in the upper part of the supply container above the sump 5 which serves to suspend a frame 6. The side walls of the frame, which may be perforated, extend nearly to the bottom of the sump 5. Within the frame `6, preferably at its lower end, a gear pump 7 is arranged the intake of which is denoted with 8. The outlet 9 of the gear pump communicates with a feed duct 10 which is led upwardly out of the frame. An overow duct 11 is connected with the upper cover of the frame 6. At the same time the upper cover of the frame 6 sealingly closes the opening in the supply container. Furthermore the supply container 1 may be provided with a filling opening which is not shown in the drawings.

The apparatus housing 2 comprises in the illustrated form of embodiment a bath container 12 which includes for instance not illustrated guide elements for guiding the layer carriers, i.e. the upper sheets or the like carrying light sensitive layers. In the drawing only those parts are shown that are essential for the invention.

The bath container is provided with a sump 13 into which the feed duct 10 reaches which extends above the upper edge of the bath container 12, and is led within the bath container downwardly. For instance, the part 14 of the feed duct provided with an elbow and forming a connection with the bath container 12 may be arranged so as to receive the part 10, sealing means being provided forming a fluid tight connection. A pipe 15 ends at the height of the liquid level in the bath container 12, and is connected by an elbow 16 with the overflow duct 11.

The pump 7 is driven by a shaft 17 extending from the frame 6 through an opening in the bottom of the housing 2 into this housing. Within the housing 2 a drive motor 18 is arranged above the frame which is connected with the shaft 17 by a disconnectable clutch 19. The support of the drive motor is arranged at one side of the frame 6 and constructed so that the drive motor 18 may be swung out of this Zone. Above the frame 6 an opening which may be closed has been provided preferably in the bottom of the housing 2 which is dimensioned so that the frame 6, after the clutch 19 has been disengaged, and the drive motor has been swung 4- sidewardly, may be removed upwardly through the bottom of the housing 2. This facilitates cleaning and supervision.

At the bottom side of the housing 2 feet 21, 22 are provided which are placed on the supply container forming the support 1. At the upper side of the support guides are provided which for instance have the form of profiles or extensions serving to tix the feet of the housing 2. By means of the feet an air gap is formed between the support and the housing 2 so that heat dissipation is possible, which is assisted specially by the fact, that the supply container is made of material having a good coefficient of heat conductivity.

It is to be understood that the motor 18 may at the same time be used for driving other rotating parts of the apparatus.

When the apparatus is switched on the motor 18 starts running and drives the gear pump 7. By means of this liquid is pumped via the feed duct 10, 14 into the bath container 12. After the liquid has reached its predetermined level the uninterruptedly discharged superfluous volume of liquid is returned into the supply container 1 via the overflow duct 15, so that an exact liquid level is maintained at a constant liquid circulation.

When the apparatus is switched off also the gear pump is stopped. Now the feed duct 10, 14 acts as a Siphon, and the liquid contained in the bath container 12 ows back into the supply container 1. It is to be noted that the gear pump used shows sufficient play to permit this backow. Furthermore it should be noted that an interruption of the liquid column is not possible as the pump is arranged in the lower part of the supply container 1.

The arrangement described shows for a relatively flat form of the supply container and customary dimensioning of the apparatus a capacity of about 12-15 liters of developing liquid which means a supply that will last for several months. Due to the fact that the liquid is returned after the pump stops losses due to evaporation are extremely small, so that a supply ready for use may be stored for several months.

In FIG. 3 another form of embodiment is illustrated. The supply container 23 is arranged within a cabinet 24 of a working table 25 on the plate of which the bath container and the squeezing roller arrangement of the developing apparatus are supported. The mentioned parts supported on the table 25 are arranged Within the housing 26.

The filling opening provided in the upper part of the supply container is covered by the closure 28 provided with a bore 27 for the passage of air. Also mounted in the closure 28 are the pipe 29 for the feed duct and the pipe 31 for the overflow duct 32.

The pipe 29 communicates with the feed duct 33 for the liquid 34 to be discharged, the feed duct 33 extending directly above the bottom of the supply container 23. The pipe 31 communicates with the overflow duct 32 which has a connecting piece 35.

The flexible oating cover 36 is provided with an aperture for the feed duct 33 and protects the liquid surface in the supply container against the air column within the container. The floating cover consists for instance of liquid tight cellular rubber or cellular PVC (chloride of polyvinyl).

The feed duct 30 leads via the gear pump 37, arranged on the lower side of the cabinet 24, and provided with the intake 38 and the discharge 39, to the bath container 40. The gear pump 37 is driven by a not shown motor arranged behind the pump. The bath container 40 is arranged within the housing 26 behind the exposure part 41 and comprises a sump 42 into which the feed duct 36 extends. The mouth of a tubular extension 43 is situated at the height of the uid level of the bath container 40 said extension 43 communicating via the rectangularly shaped overflow channel 44 with the overflow duct 32. It is to be noted, that not illustrated guide elements for leading layer carriers through the liquid bath and a not shown squeezing roller pair for pressing the layer carriers together and removing the developing liquid as well as transporting the pressed layer carriers out of the bath container 40 have been provided with in the bath container 40.

The lockable cabinet 24, as may be seen from FIG. 3 is arranged on one side of the table 2S below the table plate thus providing a free space into which the operator may stretch his legs. The connecting openings passing through the table plate open into the cabinet so that the connection ducts are not visible. The pump 37 together with its drive motor is arranged below the bottom' of the cabinet, so that the bottom forms a smooth surface and is completely available for placing the supply container 23. If the ducts 30 and 32 are made of flexible material the closure 28 is easily removable, thus facilitating the exchange of the supply container. In this connection a detachable connection is particularly suitable for fastening the feed duct 33 to the closure 2S.

When the exposure part 41 and the not shown pair of rollers are switched on by actuating the switch 45, whereby the exposure part as well as the rollers are driven by a not shown electromotor arranged within the housing 26, the motor of the gear pump 37 is started via an electrical feed line. This causes liquid to be discharged into the bath container 40 via the feed ducts 33 and 30. After the liquid has reached its predetermined level the superliuously discharged liquid is returned via the overflow pipe 43 into the supply container 23, so that an exact fluid level is maintained at a constant circulation of the fluid.

When the exposure part 41 and the rollers are switched off by actuating the switch 45 the motor for the gear pump is also stopped. Now the feed duct 3@ acts as a siphon and the liquid contained in the bath container 40 flows back into the supply container 23. For this purpose the gear pump has sufficient play to allow this return flow, while the air opening 27 serves to prevent an increase of pressure when the liquid rises again in the supply container 23.

Due to the fact, that after every stop of the pump the liquid returns, losses by evaporation or oxidation are extremely small, so that a well functioning supply of developing liquid is maintained for a long time.

FIG. 4 shows a special structure of the supply container which according to FIG. 3 is 'denoted with 23. The outer structure of the supply container corresponds to that Shown in FIG. 3. The only difference consists in the cover of the liquid within the `supply container. The form of embodiment according to FIG. 4 provides an especially advantageous structure using iioating balls which float on the surface of the liquid in la contacting manner thus providing a complete cover of the fluid. The special advantage of this form of embodiment must be seen in the fact, that uid returned via the overflow duct, the extension pipe of which is ydenoted with 47, may easily pass the coverage 46 consisting of separate floating elements, as these elements may easily yield. Furthermore these elements may be used for varying cross sectional forms of supply containers, without necessitating that a special cover must be made in correspondence with the container form. Therefore by means of this the costs for such a floating coverage are decreased. In addition the advantage is gained, that during operation no wedging or tilting can occur.

What I claim is:

1. 'In an apparatus for developing exposed photographic sheet material, an open top receptacle for a development bath having an exposed surface of substantial area, a supply container for development liquid disposed below said bath receptacle, means defining a sump at the bottom of said bath receptacle, conduit means delining a siphon extending from said sump over the edge of said bath receptacle to the vicinity of the bottom of said supply container, pump means in the lowest portion of said conduit means for pumping development iiuid from said supply container into said bath receptacle, and means in said bath receptacle for controlling the surface level of said development bath, said pump means being constructed with sufficient leakage clearance to enable com paratively rapid and complete automatic emptying of said bath receptacle by siphoning through said conduit means and pump means when the operation of said pump means is interrupted.

2. T he apparatus as set forth in claim 1, in which said pump means is disposed within said supply container.

3. The apparatus as set forth in claim l, in which said pump means is disposed outside said supply container below the bottom thereof.

4. The apparatus as set forth in claim 2, including a removable cover for a top opening in said supply container, a sump in said supply container substantially straight below said cover, and frame members depending from said cover and extending into said sump, said pump means being secured to said frame members in such a position that said pump means is disposed at least partly within said sump in the supply container when said cover is in its closing position.

5 In an apparatus for developing exposed photographic sheet material, an open top receptacle for a development bath having an exposed surface of substantial area, a supply container for development liquid disposed below said bath receptacle, means defining a sump at the bottom of said bath receptacle, conduit means defining a siphon extending from said sump over the edge of said bath receptacle to the vicinity of the bottom of said supply container, pump means in the lowest portion of said conduit means for pumping development liuid from said supply container into said bath receptacle, means in said bath receptacle for controlling the surface level of said development bath, said pump means being constructed with sufiicient leakage clearance to enable comparatively rapid and complete automatic emptying of said bath receptacle by siphoning through said conduit means and pump means when the operation of said pump means is interrupted, a removable cover for a top opening in said supply container, a sump in said supply container substantially straight below said cover, frame members depending from said cover and extending into said sump, said pump means being secured to said frame members in such a position that said pump means is disposed at least partly within said sump in the supply container when said cover is in its closing position, motor means for driving said pump means disposed above said cover and at the side of said bath receptacle, a drive shaft extending through said cover and connecting said pump means with said motor means, said drive shaft comprising a lower and an upper part, means releasably interconnecting said lower and upper parts of said drive shaft, and mounting means for said motor means adapted to enable movement of said motor means from its normal position when said means interconnecting said parts of the drive shaft is released.

6. The apparatus as set forth in claim l, in which said means for controlling the surface level in said bath receptacle comprises an overflow conduit leading downwardly into said supply container.

References Cited in the tile of this patent UNITED STATES PATENTS 359,502 Denison Mar. 15, 1887 1,922,117 Turner Aug. 15, 1933 2,621,572 Luboshez Dec. 16, 1952 2,696,771 Frantz Dec. 15, 1954 2,710,832 Harr June 14, 1955 FOREIGN PATENTS 762,807 Great Britain Dec. 5, 1956 

